JP5195320B2 - Digital FPU receiving apparatus and receiving method - Google Patents

Description

  The present invention relates to a digital FPU receiving apparatus and receiving method, and more particularly to a digital FPU receiving apparatus and receiving method capable of automating band setting.

  A digital FPU (Field Pickup Unit) receiver configured as shown in FIG. 14 is known as a microwave broadcast wave relay device (see, for example, Patent Document 1).

  The digital FPU receiver shown in FIG. 14 has a low noise amplifier 2 that amplifies a microwave band SHF (Super High Frequency) signal input from the SHF IN terminal 1 and a predetermined noise SHF signal output from the low noise amplifier 2. A band-pass filter (BPF) 3 for filtering a signal in a frequency band, a mixer 4, a local oscillator 5 for oscillating and outputting a predetermined local oscillation frequency to the mixer 4, and a signal in a predetermined frequency band from the output signal of the mixer 4 A bandpass filter (BPF) 6 for filtering, an IF amplifier 7 for amplifying the output signal of the bandpass filter, a demodulator 8, a decoder 9, a reception channel (CH) setting switch 10, a band setting switch 11, The local oscillator control unit 12 controls the oscillation frequency of the local oscillator 5.

  The operation of this digital FPU receiver will be described. The SHF IN terminal 1 receives an SHF signal which is a digital broadcast wave signal in the SHF band as an input and supplies it to the low noise amplifier 2. The low noise amplifier 2 amplifies the SHF signal to a certain level with low noise and supplies it to the bandpass filter 3. The band pass filter 3 removes an image unnecessary wave component from the SHF signal input from the low noise amplifier 2.

The mixer 4 mixes the SHF signal output from the bandpass filter 3 and the local oscillation frequency output from the local oscillator 5 to convert the SHF signal into an intermediate frequency (IF) signal. The bandpass filter 6 has, for example, a pass frequency characteristic with a center frequency f ₀ of 140 MHz and a pass bandwidth BW of 20 MHz. The band pass filter 6 filters the IF signal output from the mixer 4 to generate a local leak signal or image in the IF signal. Remove unnecessary signal components such as signals. The IF amplifier 7 receives the IF signal output from the bandpass filter 6 as an input, amplifies the IF signal to a certain level, and then outputs it to the demodulator 8. The demodulator 8 demodulates the IF signal into a digital signal and then outputs it to the decoder 9. The decoder 9 expands the demodulated digital signal, separates the video signal and the audio signal and outputs them separately.

The local oscillator control unit 12 variably controls the local oscillation frequency output from the local oscillator 5 from the information from the reception CH setting switch 10 and the information from the band setting switch 11. The reception CH setting switch 10 adjusts the reception channel according to the setting of the opposing digital FPU receiver. Further, in order to demodulate the demodulation unit 8, you must set the center frequency _{f IF} of the IF signal to 140 MHz, therefore, as the center frequency _{f IF} of the IF signal output from the mixer 4 becomes 140 MHz, the bandwidth The setting switch 11 is operated to set the local oscillation frequency output from the local oscillator 5.

  Further, depending on the modulation method, the band setting switch 11 includes a mode for performing material transmission using the entire licensed radio frequency band (hereinafter referred to as a full mode) and a lower side in the licensed radio frequency band. A mode in which material transmission is performed using only half of the band (hereinafter referred to as lower half mode) and a mode in which material transmission is performed using only the upper half of the licensed radio frequency band (hereinafter referred to as “lower half mode”). , The upper half mode is set.

  The FPU receiver includes an FPU receiver that can reduce degradation of transmission quality due to interference of adjacent waves (see, for example, Patent Document 2), and a bandpass filter that removes unnecessary frequency components from IF signals. A first bandpass filter having a wideband pass frequency characteristic and a second bandpass filter having a narrowband pass frequency characteristic are provided, and one of them is automatically selected according to the reception status of the received signal. An FPU receiver (see, for example, Patent Document 3) is also known.

JP 2008-092386 A JP 2008-219364 A JP 2000-078039 A

However, in the digital FPU receiving apparatus shown in FIG. 14, the operation of setting a band does not exist in the existing analog FPU receiving apparatus and is not so common as a wireless device. Even if the reception channel of the reception device is set by the reception CH setting switch 10, the band setting operation by the band setting switch 11 may be forgotten. In this case, since the local oscillation frequency output from the local oscillator 5 is not set correctly, the center frequency f _{IF of the} IF signal input to the demodulator 8 is not set to 140 MHz and cannot be demodulated by the demodulator 8. Note that the FPU receivers described in Patent Documents 2 and 3 do not disclose the bandwidth setting itself by the bandwidth setting switch 11.

  The present invention has been made in view of the above points, and an object thereof is to provide a digital FPU receiving apparatus and receiving method capable of automating band setting.

  In order to achieve the above object, the digital FPU receiving apparatus of the present invention includes a full mode in which material transmission is performed using the entire licensed radio frequency band, and only a part of the licensed radio frequency band. Among a plurality of types of half modes that perform material transmission using a receiver, a receiving means for receiving a radio frequency signal set to one mode, an oscillating means for oscillating a local oscillation frequency, and a wireless received by the receiving means Mixing means for frequency conversion by mixing a frequency signal with a local oscillation frequency, demodulating means for demodulating an intermediate frequency signal of a predetermined intermediate frequency, and receiving the signal output from the mixing means as an input, and the frequency band of the input signal Band identification means for identifying one mode of the radio frequency signal received by the reception means and outputting a band identification signal, and one mode indicated by the band identification signal Characterized by having a local oscillation frequency control means for variably controlling so that the intermediate frequency signal is outputted to the local oscillation frequency for frequency conversion in the mixing means a radio frequency signal from the mixing means.

  In order to achieve the above object, the digital FPU reception method of the present invention includes a full mode in which material transmission is performed using the entire licensed radio frequency band, and a part of the licensed radio frequency band. A reception step for receiving a radio frequency signal set to one mode among a plurality of types of half modes that perform material transmission using only a band, and a frequency obtained by mixing the received radio frequency signal with a local oscillation frequency. The conversion step and the reception signal frequency-converted in the mixing step are received as input, and one mode of the received radio frequency signal is identified and a band identification signal is output based on the frequency band of the input reception signal. Band identification step, and an intermediate frequency signal having a predetermined intermediate frequency when the radio frequency signal of one mode indicated by the band identification signal is frequency-converted in the mixing step And the local oscillation frequency control step of variably controlled to be output, characterized in that it comprises a demodulation step of demodulating the intermediate frequency signal.

  According to the present invention, a band is identified from a signal obtained by mixing a received radio frequency signal with a local oscillation frequency by a mixing unit to identify a mode of the radio frequency signal, and the local oscillation frequency is mixed from the identification result. By converting the means into an intermediate frequency signal having a center frequency that can be demodulated by the demodulator, the band setting can be automated, and the problem that the received signal cannot be demodulated normally by forgetting the band setting can be solved.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 shows a block diagram of a first embodiment of a digital FPU receiver according to the present invention. In the figure, the same components as those in FIG. 14 are denoted by the same reference numerals. The digital FPU receiving apparatus 100 according to the present embodiment is a digital FPU receiving apparatus that selectively uses the full mode, the lower half mode, and the upper half mode according to the operation status, and is the digital FPU receiving apparatus illustrated in FIG. Compared to FIG. 5, the band identification circuit 21 is provided, and the local oscillator control unit 22 is configured so that the local oscillation frequency output from the local oscillator 5 from the output signal of the band identification circuit 21 and the information from the reception CH setting switch 10. The band setting switch 11 is deleted by adopting a configuration for variably controlling.

  The band identification circuit 21 identifies the full mode, the lower half mode, or the upper half mode from the IF signal input from the bandpass filter 6, and outputs the identified result to the local oscillator control unit 22. Here, the full mode is a mode in which material transmission is performed using the entire licensed radio frequency band, as shown in the frequency spectrum of the transmission band in FIG. The lower half mode is a mode in which material transmission is performed using only the lower half of the licensed radio frequency band, as shown in FIG. 3 showing the frequency spectrum of the transmission band. Further, the upper half mode is a mode in which material transmission is performed using only the upper half of the licensed radio frequency band as shown in the frequency spectrum of the transmission band in FIG.

  For example, as shown in FIG. 5, the band identification circuit 21 includes a two-distributor 211, an upper narrowband bandpass filter 212, an upper detector 213, a lower narrowband bandpass filter 214, a lower detector 215, and a band identification. The circuit configuration is composed of the unit 216.

The two distributors 211 distribute the IF signal input to the band identification circuit 21 into two, one being input to the upper narrowband bandpass filter 212 and the other being input to the lower narrowband bandpass filter 214. The upper narrow band-pass filter 212 in the band identification circuit 21 of FIG. 5 has a pass frequency characteristic with a center frequency f ₀ of 145 MHz and a pass bandwidth BW of 10 MHz as shown in FIG. Output to the upper detector 213. The upper detector 213 detects the level of the input signal and outputs the detection result to the band identification unit 216.

On the other hand, the lower narrow band-pass filter 214 has a pass frequency characteristic with a center frequency f ₀ of 135 MHz and a pass bandwidth BW of 10 MHz, as shown in FIG. Output to. The lower detector 215 detects the level of the input signal and outputs the detection result to the band identification unit 216.

  Based on the detection results of the upper detector 213 and the lower detector 215, the band identifying unit 216 identifies the upper half mode when the signal is detected only by the upper detector 213, and the signal is detected only by the lower detector 215. Is detected as the lower half mode, and when the signal is detected by both the upper detector 213 and the lower detector 215, it is identified as the full mode, and the identification result is output.

Returning to FIG. The local oscillator control unit 22 variably controls the local oscillation frequency output from the local oscillator 5 based on the information from the reception CH setting switch 10 and the identification result from the band identification circuit 21. Specifically, when the reception CH setting switch 10 is set, the local oscillator control unit 22 can receive a full-mode signal of the selected CH (f _CH ) based on information from the reception CH setting switch 10. The local oscillation frequency output from the local oscillator 5 is controlled to be (f _CH −140) MHz.

After that, the local oscillator control unit 22 shifts the local oscillation frequency output from the local oscillator 5 from (f _CH −140) MHz by −5 MHz when the identification result from the band identification circuit 21 is the lower half mode. Control is performed to (f _CH -145) MHz. When the identification result from the band identification circuit 21 is the upper half mode, the local oscillator control unit 22 shifts the local oscillation frequency output from the local oscillator 5 from (f _CH −140) MHz by +5 MHz, f _CH -135) The frequency is controlled to be MHz.

  Next, the operation of this embodiment shown in FIG. 1 will be described. In FIG. 1, an SHF signal, which is a digital broadcast wave signal input from an SHF IN terminal 1, is input to a low noise amplifier 2, amplified to a certain level, and then input to a bandpass filter 3 to generate an image unnecessary wave. Ingredients are removed. The mixer 4 mixes the SHF signal from the bandpass filter 3 and the local oscillation frequency from the local oscillator 5, and frequency-converts the SHF signal into an IF signal. The signal from the mixer 4 is input to the band pass filter 6.

The bandpass filter 6 has, for example, a pass frequency characteristic with a center frequency f ₀ of 140 MHz and a pass bandwidth BW of 20 MHz. The band pass filter 6 filters the IF signal output from the mixer 4 to generate a local leak signal or image in the IF signal. Remove unnecessary signal components such as signals. The IF amplifier 7 receives the IF signal output from the bandpass filter 6 as an input, amplifies the IF signal to a certain level, and then outputs it to the demodulator 8. The demodulator 8 demodulates the IF signal into a digital signal and then outputs it to the decoder 9. The decoder 9 expands the demodulated digital signal, separates the video signal and the audio signal and outputs them separately.

On the other hand, similarly to the IF amplifier 7, the band identification circuit 21 receives the IF signal output from the bandpass filter 6 as an input, and identifies whether the IF signal is a full mode, a lower half mode, or an upper half mode, The identified result is output to the local oscillator control unit 22. Here, it is assumed that the SHF signal having the center frequency f ₀ of 7005 MHz, the band BW of 10 MHz and the band setting of the upper half mode of the frequency spectrum indicated by I in FIG.

From the CH setting information from the reception CH setting switch 10, the local oscillator control unit 22 sets the local oscillation frequency f _LO output from the local oscillator 5 to 6860 MHz so that a full mode signal of the selected CH can be received. . The upper half-mode SHF signal is mixed with the local oscillation frequency of 6860 MHz output from the local oscillator 5 by the mixer 4 and converted into an IF signal. Thereby, an IF signal having a center frequency f _IF of 145 MHz and a band BW of 10 MHz in the frequency spectrum indicated by II in FIG. 9 is extracted from the band pass filter 6 and input to the IF amplifier 7 and the band identification circuit 21 respectively. The

  The band identification circuit 21 having the configuration of FIG. 5 converts the input IF signal into an upper narrowband bandpass filter 212 having the frequency characteristics shown in FIG. 6 and a lower narrowband bandpass having the frequency characteristics shown in FIG. To the filter 214. Since the IF signal input at this time is an IF signal having a center frequency of 145 MHz and a bandwidth of 10 MHz in the frequency spectrum of FIG. 9, an IF signal of a predetermined value or more is filtered only by the upper narrowband bandpass filter 212, and the Upper After being detected by the wave detector 213, it is supplied to the band identification unit 216. On the other hand, a detection signal of a predetermined level or higher is not supplied from the lower detector 215 to the band identification unit 216. As a result, the band identifying unit 216 identifies the upper half mode and outputs the identification result to the local oscillator control unit 22.

When the local oscillator control unit 22 receives the upper half mode identification result from the band identification unit 21 as an input, the local oscillator control unit 22 receives the local oscillation frequency f _LO output from the local oscillator 5 by the reception CH setting switch 10. Is shifted by +5 MHz from 6860 MHz according to the above, and set to 6865 MHz. As a result, the IF signal that is generated by being mixed by the mixer 4 and then extracted from the bandpass filter 6 is an IF signal in a normal frequency band having a center frequency f _IF of 140 MHz and a band BW of 10 MHz shown in FIG. Become. Therefore, the demodulator 8 can normally demodulate the IF signal.

Next, it is assumed that an SHF signal having a center frequency f ₀ of 7000 MHz, a band BW of 20 MHz, and a band setting of full mode is received from the SHF IN terminal 1 in the frequency spectrum indicated by IV in FIG.

From the CH setting information from the reception CH setting switch 10, the local oscillator control unit 22 sets the local oscillation frequency f _LO output from the local oscillator 5 to 6860 MHz so that a full mode signal of the selected CH can be received. . Thus, the full mode SHF signal is mixed with the local oscillation frequency 6860 MHz output from the local oscillator 5 by the mixer 4 and is frequency-converted to an IF signal. Thus, an IF signal having a center frequency f _IF of 140 MHz and a band BW of 20 MHz in the frequency spectrum indicated by V in FIG. 12 is extracted from the band pass filter 6 and input to the IF amplifier 7 and the band identification circuit 21 respectively. The

  The band identification circuit 21 having the configuration of FIG. 5 converts the input IF signal into an upper narrowband bandpass filter 212 having the frequency characteristics shown in FIG. 6 and a lower narrowband bandpass having the frequency characteristics shown in FIG. To the filter 214. Since the IF signal input at this time is an IF signal having a center frequency of 140 MHz and a bandwidth of 20 MHz in the frequency spectrum of FIG. 12, a predetermined value is obtained from both the upper narrowband bandpass filter 212 and the lower narrowband bandpass filter 214. The above IF signal is filtered, detected by the upper detector 213 and the lower detector 215, and then supplied to the band identification unit 216. Thereby, the band identifying unit 216 identifies the full mode and outputs the identification result to the local oscillator control unit 22.

When the local oscillator control unit 22 receives the full mode identification result from the band identification unit 21 as an input, the local oscillator control unit 22 does not change the local oscillation frequency f _LO output from the local oscillator 5 and continues to set it to 6860 MHz. As a result, the band-pass filter 6 outputs an IF signal in a normal frequency band with a center frequency f _IF of 140 MHz and a band BW of 20 MHz. For this reason, the demodulator 8 can normally demodulate the input IF signal.

Even when an SHF signal having a center frequency f ₀ of 6995 MHz, a band BW of 10 MHz, and a band setting of Lower half mode is received from the SHF IN terminal 1, the mixer 4 can locally after being mixed with the local oscillation frequency 6860MHz output from the oscillator 5, IF signal unnecessary frequency components by a band-pass filter 6 is taken out is removed, the center frequency _{f IF} is 135MHz, the bandwidth BW is 10 MHz.

  Accordingly, an IF signal having a predetermined value or more is filtered only by the lower narrow band-pass filter 214 in the band identifying circuit 21, detected by the lower detector 215, and then supplied to the band identifying unit 216. On the other hand, a detection signal of a predetermined level or higher is not supplied from the upper detector 213 to the band identification unit 216. As a result, the band identifying unit 216 identifies the lower half mode and outputs the identification result to the local oscillator control unit 22.

When the local oscillator control unit 22 receives the identification result of the lower half mode as an input from the band identification unit 21, the local oscillator control unit 22 receives the local oscillation frequency f _LO output from the local oscillator 5 by the reception CH setting switch 10. Is shifted by -5 MHz from 6860 MHz according to the above, and set to 6855 MHz. As a result, the IF signal that is generated by being mixed by the mixer 4 and then extracted from the bandpass filter 6 becomes an IF signal in a normal frequency band with a center frequency f _IF of 140 MHz and a band BW of 10 MHz. Therefore, the demodulator 8 can normally demodulate the IF signal.

  As described above, according to the present embodiment, the band identification circuit 21 identifies the full mode signal, the lower half mode signal, or the upper half mode signal from the received SHF signal, and based on the identification result. Then, the output local oscillation frequency of the local oscillator 5 at the time of frequency conversion (mixing) of the received SHF signal to the IF signal is changed, and the demodulator 8 converts it to an IF signal having a center frequency that can be demodulated. For this reason, according to the present embodiment, the band setting is automatically performed only by setting the reception CH. Therefore, even if the reception CH is set, the received SHF signal is normally demodulated by forgetting the band setting. Can solve the problem of not being able to.

(Second Embodiment)
FIG. 13 shows a block diagram of a second embodiment of the digital FPU receiver according to the present invention. In the figure, the same components as those in FIG. The digital FPU receiving apparatus 200 of the present embodiment is different from the digital FPU receiving apparatus 100 of the first embodiment shown in FIG. 1 in that the band identification circuit 23 performs band identification from the IF signal amplified by the IF amplifier 7. . The band identification circuit 23 has the same configuration as that of the band identification circuit 21 shown in FIG. 5, and identifies and identifies the full mode, the lower half mode, or the upper half mode from the IF signal input from the IF amplification unit 7. The result is output to the local oscillator control unit 22.

  As a result, the present embodiment also identifies whether the received SHF signal is a full mode signal, a lower half mode signal, or an upper half mode signal from the received SHF signal by the band identification circuit 21, as in the first embodiment. Based on the identification result, the output local oscillation frequency of the local oscillator 5 when the received SHF signal is frequency-converted (mixed) into an IF signal is changed, and converted to an IF signal having a center frequency that can be demodulated by the demodulator 8 Therefore, even if the reception CH is set, the problem that the received SHF signal cannot be demodulated normally can be solved by forgetting the band setting.

  Note that the present invention is not limited to the above embodiment, and for example, a signal output from the mixer 4 and input to the bandpass filter 6 may be branched and input to the band identification circuit 21. The signal output from the mixer 4 and supplied to the bandpass filter 6 includes unnecessary signal components such as a local leak signal and an image signal in addition to the IF signal. This is because it is removed by the upper narrowband bandpass filter 212 and the lower narrowband bandpass filter 214 in the circuit 21, and only the necessary IF signals can be frequency-selected.

1 is a block diagram of a first embodiment of a digital FPU receiver of the present invention. It is a figure explaining the transmission band of a full mode. It is a figure explaining the transmission band of Lower half mode. It is a figure explaining the transmission band of Upper half mode. It is a block diagram of one Embodiment of the band identification circuit in FIG. It is a figure which shows an example of the pass frequency characteristic of the narrow band pass filter for Upper in FIG. It is a figure which shows an example of the pass frequency characteristic of the narrow band pass filter for Lower in FIG. It is a figure which shows the frequency spectrum of the received Upper half mode signal. FIG. 9 is a diagram illustrating a frequency spectrum of the IF signal of FIG. 1 before the control of the local oscillator in FIG. 1 when the Upper half mode signal of FIG. 8 is received. FIG. 9 is a diagram illustrating a frequency spectrum of the IF signal in FIG. 1 after control of the local oscillator in FIG. 1 when the Upper half mode signal in FIG. 8 is received. It is a figure which shows the frequency spectrum of the received full mode signal. FIG. 12 is a diagram showing the frequency spectrum of the IF signal of FIG. 1 before and after control of the local oscillator in FIG. 1 when the full mode signal of FIG. 11 is received. It is a block diagram of 2nd Embodiment of the digital FPU receiver of this invention. 10 is a block diagram of an example of a digital FPU receiving device described in Patent Literature 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 SHF IN terminal 2 Low noise amplifier 3, 6 Band pass filter 4 Mixer 5 Local oscillator 7 IF amplifier 8 Demodulator 9 Decoder 10 Reception CH setting switch 21, 23 Band identification circuit 22 Local oscillator control part 100, 200 Digital FPU receiver 211 2 Divider 212 Upper Narrow Bandpass Filter 213 Upper Detector 214 Lower Narrow Bandpass Filter 215 Lower Detector 216 Band Identification Unit

Claims (10)

One of the full mode that transmits the material using the entire licensed radio frequency band and the half mode that transmits the material using only a part of the licensed radio frequency band. Receiving means for receiving a radio frequency signal set in the mode of
An oscillation means for oscillating the local oscillation frequency;
Mixing means for mixing and converting the radio frequency signal received by the receiving means with the local oscillation frequency;
Demodulation means for demodulating an intermediate frequency signal of a predetermined intermediate frequency;
Band that receives the signal output from the mixing means as an input, identifies the one mode of the radio frequency signal received by the receiving means based on the frequency band of the input signal, and outputs a band identification signal An identification means;
Local oscillation frequency control for variably controlling the local oscillation frequency for converting the frequency signal of the one mode indicated by the band identification signal by the mixing unit so that the intermediate frequency signal is output from the mixing unit And a digital FPU receiving apparatus. A full mode that transmits material using the entire licensed radio frequency band, a first half mode that transmits material using only the lower half of the licensed radio frequency band, and a licensed mode. Receiving means for receiving a radio frequency signal set to one of the three modes of the second half mode for performing material transmission using only the upper half band of the radio frequency band;
Channel setting means for setting a desired reception channel;
An oscillation means for oscillating the local oscillation frequency;
Mixing means for mixing and converting the radio frequency signal received by the receiving means with the local oscillation frequency;
Demodulation means for demodulating an intermediate frequency signal of a predetermined intermediate frequency;
Band that receives the signal output from the mixing means as an input, identifies the one mode of the radio frequency signal received by the receiving means based on the frequency band of the input signal, and outputs a band identification signal An identification means;
When the full mode radio frequency signal of the reception channel set by the channel setting means is received, the local oscillation frequency is variably controlled so that the intermediate frequency signal is output from the mixing means, and the band identification is performed. When the signal is supplied, the intermediate frequency signal is output from the mixing unit with the local oscillation frequency for frequency conversion of the radio frequency signal of the one mode indicated by the band identification signal by the mixing unit. And a local oscillation frequency control means for variably controlling the digital FPU receiver. Filter means for removing unnecessary frequency components from the signal output from the mixing means and filtering the intermediate frequency signal of the intermediate frequency;
Amplifying means for amplifying the intermediate frequency signal output from the filter means and outputting the amplified signal to the demodulating means, wherein the band identifying means is an input signal of the filter means, and the intermediate signal output from the filter means Receiving one of a frequency signal and the amplified intermediate frequency signal output from the amplifying means as an input, identifying the one mode, and outputting the band identification signal. Item 3. The digital FPU receiver according to Item 1 or 2. The band identification means includes
Distribution means for distributing a plurality of input signals;
The signal distributed by the distributing means is received as an input, and the receiving means passes through the frequency band of the input signal when receiving the radio frequency signal of each type of half mode among the plurality of types of half modes. A plurality of band-pass filter means as frequency bands;
Identification means for identifying the one mode of the radio frequency signal received by the reception means and outputting a band identification signal based on the comparison result of the output signal levels of the plurality of bandpass filter means The digital FPU receiving apparatus according to claim 1 or 3, characterized in that The band identification means includes
A distribution means for distributing the input signal into two;
The first frequency signal in the first half mode is received by the receiving unit as one input signal that has been distributed in two by the distributing unit, and the frequency band of the input signal is a pass frequency band. 1 bandpass filter means;
When the other signal distributed by the distribution means is received as an input and the radio frequency signal in the second half mode is received by the reception means, the frequency band of the input signal is set as a pass frequency band. Two bandpass filter means;
Identification for identifying the one mode of the radio frequency signal received by the receiving means and outputting a band identification signal based on the comparison result of the output signal levels of the first and second bandpass filter means The digital FPU receiver according to claim 2 or 3, further comprising: means. One of the full mode that transmits the material using the entire licensed radio frequency band and the half mode that transmits the material using only a part of the licensed radio frequency band. Receiving a radio frequency signal set to the mode of
A mixing step of mixing the received radio frequency signal with a local oscillation frequency to convert the frequency;
Band identification for receiving the reception signal frequency-converted in the mixing step as input, and identifying the one mode of the received radio frequency signal based on the frequency band of the input reception signal and outputting a band identification signal Steps,
A local oscillation frequency control step for variably controlling the intermediate frequency signal of a predetermined intermediate frequency when the radio frequency signal of the one mode indicated by the band identification signal is converted in the mixing step;
And a demodulating step for demodulating the intermediate frequency signal. A full mode that transmits material using the entire licensed radio frequency band, a first half mode that transmits material using only the lower half of the licensed radio frequency band, and a licensed mode. A receiving step of receiving a radio frequency signal set to one of the three modes of the second half mode for performing material transmission using only the upper half of the radio frequency band; and
A mixing step of mixing the received radio frequency signal with a local oscillation frequency to convert the frequency;
Band identification step for receiving the reception signal frequency-converted in the mixing step as input, identifying the one mode of the received radio frequency signal based on the frequency band of the input signal, and outputting a band identification signal When,
When the reception channel is set by the channel setting means, the local oscillation frequency is variably controlled so that the intermediate frequency signal is output when the full-mode radio frequency signal of the reception channel is frequency-converted by the mixing step. Then, when the band identification signal is supplied, the local oscillation frequency for frequency-converting the radio frequency signal of the one mode indicated by the band identification signal in the mixing step is converted by the frequency conversion in the mixing step. A local oscillation frequency control step for variably controlling the intermediate frequency signal to be output;
And a demodulating step for demodulating the intermediate frequency signal. The band identification step includes:
The reception signal obtained by frequency conversion by the mixing step, the intermediate frequency signal of the intermediate frequency filtered by removing unnecessary frequency components from the reception signal obtained by frequency conversion by a filter means, and the filter means And receiving one of the amplified intermediate frequency signals obtained by amplifying the intermediate frequency signal output from the input, identifying the one mode, and outputting the band identification signal. 8. The digital FPU receiving method according to 6 or 7. The band identification step includes:
A distribution step of distributing a plurality of input signals;
When receiving the radio frequency signal of each type of the half mode among the plurality of types of half modes by the receiving step, a plurality of band paths each having a frequency band of the signal distributed in the distributing step as a passing frequency band A filtering step for filtering each of the distributed input signals with filter means;
An identification step of identifying the one mode of the radio frequency signal received by the reception step and outputting a band identification signal based on the comparison result of the output signal levels of the plurality of bandpass filter means 9. The digital FPU receiving method according to claim 6 or 8, wherein: The band identification step includes:
A distribution step of distributing the input signal into two;
A first band-pass filter means having a frequency band of one of the two signals distributed in the distribution step as a pass frequency band when the radio frequency signal in the first half mode is received in the reception step; A first filtering step for filtering said one signal;
A second band-pass filter means that uses the frequency band of the other signal divided into two in the distribution step as a pass frequency band when the radio frequency signal in the second half mode is received in the reception step; A second filtering step for filtering said other signal;
Identification for identifying the one mode of the radio frequency signal received by the reception step and outputting a band identification signal based on the comparison result of the output signal levels of the first and second band pass filter means The digital FPU receiving method according to claim 7 or 8, comprising the steps of:

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